In a cataract surgery a natural lens of the human eye in which a cataract has developed is replaced by an artificial lens. This is a microsurgical operation performed by a surgeon using a surgical microscope for observation. Entering through the sclera or cornea, an incision is made in the capsule sac within the inner margin of the iris and without the latter being injured. By this incision, on the one hand, the endogenous natural lens is removed by suction, for example, after ultrasonic shattering and, on the other hand, the artificial lens is inserted.
Conventionally, the incision in the capsule sac is made by the surgeon by his naked eye, namely such that the incision takes a zigzag or approximately circular course around a center of the inner margin of the iris.
There are grounds for supposing that certain complications are less likely to occur as long-term consequences of the cataract surgery if the incision in the capsule sac has a substantially circular configuration, the diameter of which is adapted to the diameter of the artificial lens to be inserted.